If it's just a productivity rig, have you tried a SSD? For general use the speed boost from one of those should swat the upgrade bug for a couple months.
Unless you like buggy BIOS (or UEFI) and the early adopter's price, you'll also want to wait a couple months AFTER the release of Haswell before you buy into the new platform. Even if you do decide to go Haswell later, the SSD you get now can transfer to the new computer. (I've transferred a single SSD between 4 computers now.)

__________________"The computer programmer says they should drive the car around the block and see if the tire fixes itself." [src]